#define  _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#define my_offsetof(a,b) ((size_t)&(((a*)0)->b))
struct S1 
{
	char a;
	int b;
}s;
int main()
{
	printf("%d\n", my_offsetof(struct S1,b));
	return 0;
}